Short answers, pulled from the story.
Human habitation in the area now known as Seoul dates back 30,000 to 40,000 years. Archaeological evidence from the Amsa-dong Prehistoric Site reveals that people lived in huts with lowered floors called umjip around 4,000 B.C.
Yi Seong-gye chose Hanyang as the new capital of Korea in September 1394 after founding the Joseon dynasty. Construction of the city began in October 1394 and major palaces including Gyeongbokgung were finished in 1395 during early construction stages.
Seoul changed hands four times between North Korean forces and American-backed South Korean forces during the Korean War. The city fell to the North Koreans in June 1950 during the First Battle of Seoul and UN forces recaptured it again in Operation Ripper during the spring of 1951.
In August 1963, Seoul annexed parts of Yangju-gun, Gwangju-gun, Siheung-gun, Gimpo-gun, and Bucheon-gun expanding the northeastern borders. In September, Seoul again annexed present-day Gangnam which more than doubled the size of Seoul from approximately 248 square kilometers to 605 square kilometers.
The city has been named the World Design Capital in 2010 and served as one of the host cities for the 2002 FIFA World Cup. It also hosted the 1986 Asian Games and the 1988 Summer Olympics while establishing the Korea World Trade Center Complex in 1988.